indicates, by increasing the weight of cost function (i. e. , (1 À γ 1 )), the number of
selected centers decreases. It means that the model tries to select the locations which
could cover the demand of applicants, though they may not have high rank in the
utility calculated by MCDM. On the other hand, when the weight of utility function
increases (i. e. , γ 1 ), all service applicants receive high-quality service from high
utility service provider.
The objective function space for different weight applied in Table 5.9 is drawn in
Fig. 5.5. In brief, by determining an appropriate weight for objective functions, not
Table 5.8 Result of model for different amount of coverage radius
Coverage radius
Selected places
Objective function
500
East Azerbaijan
0.79
South Khorasan
Kerman
Kermanshah
Kohgiluyeh and Boyer-Ahmad
Golestan
700
Razavi Khorasan
0.86
Kordestan
Kerman
Kohgiluyeh and Boyer-Ahmad
1000
Tehran
0.91
Yazd
1500
Kohgiluyeh and Boyer-Ahmad
0.95
Table 5.9 Sensitivity analysis done on the weight of objective functions
γ 1
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Utility function (Z 1 )
0.21
0.21
0.21
0.21
0.21
0.21
0.30
0.35
0.10
Cost function (Z 2 )
6
6
6
6
6
6
7
8
3 1
0
0.2
0.4
0.6
0.8
1
1.2
0
1
2
3
4
5
6
Fig. 5.5 Feasible area of objective functions for coverage radius 500
88
S. Kheybari and A. Pooya